1. Field of the Invention
The present invention relates generally to remote control systems where a user selects and transmits a direction control signal from a remote control transmitter to a remotely controlled device. More particularly, the present invention relates to an improved remote control system where the user may select a desired direction relative to an external reference direction without considering the orientation of the remote control transmitter or the remotely controlled device relative to the external reference direction.
2. Description of the Prior Art
There are many known varieties of remote control systems. Probably the first to come to mind are those used with hobby vehicle systems such as remote control planes, boats, cars, etc.
A typical prior art hobby vehicle system consists of a remote control transmitter that includes a user-operated means for selecting either "left" or "right" and for transmitting a direction control signal in response to the user selection and a remotely controlled vehicle (car, boat, plane, etc.) that responds to the transmitted direction control signal. For example, a radio controlled car is comprised of a car that may be commanded to turn left or right and a remote control transmitter from which the user may select and transmit left or right direction control commands. A typical direction selecting means consists of a joystick that may be moved either left or right relative to the remote control device. Ordinarily, the user must continuously hold the joystick in the selected direction during the entire time that the vehicle is turning and then release the joystick to end the turn.
The prior art remote control systems are burdened by the fact that the resulting direction of the vehicle is based on factors that are constantly changing relative to the user and the remote control transmitter, namely the position and direction of the vehicle. Since the position and direction of the remotely controlled vehicle are constantly varying relative to the user, the resulting direction of the vehicle, relative to the user, is also constantly varying.
Given a remote control car, for example, if a user selects and transmits a "left" or "right" direction control signal when the car is travelling radially away from the user, the resulting direction of the car, relative to the user, will correspond to the transmitted direction control signal. More specifically, if a "left" command is transmitted, the car will travel left relative to its direction and position and also relative to the user.
However, if a "left" or "right" direction control signal is transmitted to the car when it is travelling radially towards the user, the resulting direction of the car, relative to the user, is inversely related to the transmitted direction control signal. Under these circumstances, if a "left" command is transmitted, the car will travel left relative to its direction and position but will travel right relative to the user.
It can be seen from the above description that the user with an ordinary radio control system must always be conscious of the position of the vehicle and the direction that it is travelling, both before and during a turn, so that the user can rapidly engage in the mental acrobatics necessary to steer the vehicle.